This application claims the benefit of Korean Patent Application No. 10-2005-0115894, filed on Nov. 30, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to an address resolution protocol (ARP) processing method for Ethernet matching, and more particularly to, an ARP processing method via an Ethernet over a synchronous optical network/synchronous digital hierarchy (SONET/SDH) (EoS) channel in a network such as the Internet/an Intranet and a LAN in order to reduce unnecessary broadcast traffic packets for Ethernet matching.
2. Description of the Related Art
Owing to the popularization of the Internet, synchronous optical network/synchronous digital hierarchy (SONET/SDH ) equipment is required to transmit Internet protocols (IPs). Therefore, methods of transmitting the IPs have been developed using SONET/SDH equipment.
Ethernet provided by IEEE WG 802.3 is a relatively simple and cost-effective technology that connects a LAN and the Internet/an Intranet in personal and public networks. Ethernet messages including IPs are directly applied to the SONET/SDH equipment to reduce expense.
In a 4B/4B or 8B/10B encoding process, an Ethernet physical layer adds 25% overhead to a layer 2 Ethernet stream. The overhead indicates a gap between packets, a preamble, and interframe spacing (IFS) indicating the start of a packet boundary.
The IFS is an overhead of a layer 2 of an adjacent Ethernet message, and does not contain useful information in a bi-directional link. Therefore, the Ethernet message is mapped to SONET, deleted from a node adjacent to the IFS and the physical layer, and reproduced in an end, so that bandwidths can be considerably reduced.
The reduction of bandwidths compensates for a reduction of SONET bandwidths required to transmit the Ethernet message for customers that do not need Ethernet at a line speed. This is called frame mapped generic framing procedure (GFP-F) accessing.
Service providers can provide the SONET bandwidths as options by extending a basic TDM (VT1.5, STS-1, or STS-3c). Customers can obtain desired bandwidths regardless of an Ethernet port speed. As mentioned above, the GFP-F accessing cannot directly move Ethernet to SONET networks.
GFP standards allow GFP-F or GFP-transparent mapping (T) as an Ethernet over SONET/SDH (EoS) channel, whereas GFP-T standards are progressing for an effective transmission at an Ethernet line speed or to a sub rate Ethernet. Service standardization maintains 802.1 and 802.3 Ethernet and deletes encoding of the physical layer, and unnecessary overheads such as the IFS. Standardization of ITU-T and the metro Ethernet forum (MEF) are in progress.
As ITU-T G. 707 SDH standards develop, a virtual concatenation technology that accommodates bit rates of Ethernet LAN service, 10/100/bit/s, 1 Giga/10 Giga bit/s, and enables non-standard SONET/SDH multiplexing to more effectively use bandwidths has been introduced.
The Ethernet physical speed differs from a TDM speed. In order for Ethernet to include SONET, the Ethernet needs to be mapped to a greater amount of Ethernet than the Ethernet. However, such a method requires a lot of SONET transmission consumption.
For example, if 100 Mb/s Ethernet is mapped to the STS-3c (155.52 Mbps), waste of 35% is generated, and if 1 Gb/s is mapped to the STS-48c (2.5 Gbps), waste of 60% is caused. Virtual concatenation (VC) logically groups VT1.5, and obtains SONET bandwidths mapped with the Ethernet speed, thereby reducing the bandwidth consumption. For example, seven STS-3cs are logically bound to carry giga bit Ethernet subscribers using an STS-3c-7v virtual link connected pass.
The ITU-T G.707 explains the advantage presented by SDH and multiplexing, and designates a set of an SDH bit speed, a general policy and message structure of the network node interface (NNI), a whole message size of 9 row ×N×270 column, section overhead (SOH) followed with the byte allocation, an arrangement toward the international interconnection of the synchronization transport module (STM), a format regarding multiplexing and mapping of a device in NNI to STM-N.
SONET is identical to SDH in North America. In optical media, SONET is a US (ANSI) standard for synchronized data transmission. It is guaranteed that a digital network can be internationally interconnected and use the optical media according to existing conventional transmission systems attached by a branch. SONET is an optical carrier level and defines a multiple set of a known base speed and a base speed of 51.84 Mbps.
SONET has an octet synchronization multiple structure defining a standard speed and a group of formats. Standards on single fiber, and multiple mode fabric and CATV 75 ohm coaxial cable are provided. A transmission rate is an integral multiple of 51.840 Mbps and used to transfer a T3/E3 bit synchronization signal. It is strongly recommended to use G,703 E1/E3/E4/T1/T2/T4 interface as the physical layer of IP over SDH/SONET so that users can easily access a LAN.
An Ethernet interface has a MAC address to distinguish discrete hosts over a LAN. The MAC address of each of all Ethernet interfaces has a different value. Therefore, each host can be uniquely distinguished on a local network.
An EoS interface assembles an STS-1 rate that is a basic transmission speed due to a high/low order virtual order VC function and makes a variety of transport sizes. Each VC of the transport sizes is a channel.
Generally, LANs are used to communicate information between terminals using a simple message format in research institutes, companies, etc., having an interest in the matter. Unlike a conventional LAN that is simultaneously accessed by several tens or hundreds of users, broadcast/multicast packets such as ARP requests are frequently generated in a cyber apartment or a multi-tenant unit (MTU) environment that simultaneously accommodates several thousands of users. Therefore, equipment and terminals of the LAN environment must process a lot of packets regardless of the equipment and terminals.
To address the problem, a method of dividinga LAN into a plurality of virtual LANs using a router to prevent degradation of the performance of the LAN according to packets of broadcast traffic has recently been popularized.